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Aims Nonmotor symptoms (NMS) such as cognitive impairment and impulse‐control disorders in Parkinson's disease (PD) remain a therapeutic challenge. Transcranial direct current stimulation (tDCS) has emerged as a promising alternative, although its immediate effects on NMS have been less well defined. In this randomized, sham‐controlled, crossover study, we aimed to explore the single‐session tDCS effects on cognitive performance in PD. Methods Ten nondemented patients with PD completed two sessions in counterbalanced order, receiving 20 minutes of either 2 mA anodal or sham tDCS over the left dorsolateral prefrontal cortex (DLPFC). During stimulation, they performed the visual working memory and go/no‐go tasks. Performance of the tasks was compared between the two conditions. Results Single‐session anodal tDCS over the left DLPFC did not significantly improve cognitive tasks in PD compared with sham (P > .05). Conclusion Single‐session tDCS is ineffective in improving visual working memory and inhibitory control in PD. Further research may worth exploring alternative tDCS parameters, ideally with repeated sessions and concomitant training.

The posterior parietal cortex (PPC) has been associated with the encoding of events in peripersonal space, but little is known about the precise segregation of parietal areas involved specifically in 'near-space' visuospatial processing. This study applied transcranial magnetic stimulation (TMS) to two parietal areas: the right angular gyrus (ANG) and the right supramarginal gyrus (SMG) in addition to a control site, cortical visual area V5, while subjects performed symmetry judgements on lines presented simultaneously in the left and right visual fields. Eight subjects performed the task with the stimuli presented either in peripersonal or extra personal space. As expected, TMS over the right ANG caused subjects to report lines as being longer ipsilateral to the stimulation site, but only in near space. TMS of the right SMG, however, induced a bias shift in both near and far space, but the change only reached significance in near space. Our findings suggest that, consistent with its role in somatosensory functions, the SMG, like the ANG, is specialised for near space.

Transcranial magnetic stimulation (TMS) allows one to investigate the effects of temporary interference of neural processing in neurologically intact subjects. In a previous study [J. Silvanto et al. (2007) Eur. J. Neurosci., 25, 1874-1881] we found that online TMS perceptually facilitates the attributes encoded by the least active neural populations. The objective of the present experiment was to extend this work to determine whether such state-dependent effects can be observed when offline high-frequency TMS is applied to suppress neural activity. The activity levels of direction-selective neural populations in the V1/V2 region were modulated by asking subjects to passively view either leftward or rightward motion during offline TMS. In a subsequent motion direction-discrimination task, their ability to discriminate motion direction was dependent on the type of motion they had passively viewed during offline TMS: detection of the congruent direction (i.e. direction viewed during offline TMS) was unaffected, whereas detection of the incongruent direction (i.e. opposite direction to the one viewed during offline TMS) was impaired. As the activity level of neurons tuned to the incongruent direction was presumably lower during the TMS than of those tuned to the congruent direction, this behavioral result demonstrates that the offline TMS preferentially suppressed attributes encoded by the least active neural populations. In contrast to direction discrimination, motion detection was not impaired in a direction-specific manner. This shows that the requirements of the psychophysical task, in conjunction with the relative activity states of neuronal populations when TMS is applied, can be used to selectively interfere with overlapping neuronal populations.

Transcranial magnetic stimulation (TMS) is now widely used as a 'virtual' lesion paradigm to investigate behavioural functions, but the mechanisms through which it influences neural processing are unclear. To understand the differential effects of TMS on spatially overlapping populations of neurons we manipulated the relative activity levels of visual neurons by adapting subjects to a range of visual stimuli. By applying TMS to the visual cortex representing the central visual field we have shown in two experiments that the behavioural and perceptual effects of TMS depend on the state of adaptation of the neural population stimulated by TMS. Specifically, we have demonstrated that within the stimulated area TMS perceptually facilitates the attributes encoded by the less active neural population. We have demonstrated the generality of this principle for both suprathreshold and subthreshold TMS as well as for colour and orientation-contingent colour using both subjective reports and psychophsyical measures. These findings can explain how TMS disrupts cognitive functions and therefore have implications for all studies which use TMS to disrupt behaviour.

This study assessed the early mechanisms underlying perception of plaid motion. Thus, two superimposed gratings drifting in a rightward direction composed plaid stimuli whose global motion direction was perceived as the vector sum of the two components. The first experiment was aimed at comparing the perception of plaid motion when both components were presented to both eyes (dioptic) or separately to each eye (dichoptic). When components of the patterns had identical spatial frequencies, coherent motion was correctly perceived under dioptic and dichoptic viewing condition. However, the perceived direction deviated from the predicted direction when spatial frequency differences were introduced between components in both conditions. The results suggest that motion integration follows similar rules for dioptic and dichoptic plaids even though performance under dichoptic viewing did not reach dioptic levels. In the second experiment, the role of early cortical areas in the processing of both plaids was examined. As convergence of monocular inputs is needed for dichoptic perception, we tested the hypothesis that primary visual cortex (V1) is required for dichoptic plaid processing by delivering repetitive transcranial magnetic stimulation to this area. Ten minutes of magnetic stimulation disrupted subsequent dichoptic perception for approximately 15 min, whereas no significant changes were observed for dioptic plaid perception. Taken together, these findings suggest that V1 is not crucial for the processing of dioptic plaids but it is necessary for the binocular integration underlying dichoptic plaid motion perception.

Musically naive subjects were scanned using functional magnetic resonance imaging (fMRI) before and after they had been taught to read music and play keyboard. When subjects played melodies from musical notation after training, activation was seen in a cluster of voxels within the right superior parietal cortex consistent with the view that music reading involves spatial sensorimotor mapping.

2 studies of 8- and 11- year-old children explored factors related to willingness $$. Study I assessed baseline gender prefernces and gender-reiatd cognitive flexibility. While older children were found to have greater congnitive flexibility, and older boys had more stereotyped preferences, such questionnaire measures were not highly predictive of gender-atraditional behavior. Study 2 explored the parameters of vicarious social reinforcement in the symbolic modeling of gender-atraditional behavior. Peer reinforcers were more effective with younger children and on child-oriented tasks, whereas adult reinforcers were more effective with older children and on adult-oriented gender tasks. Both studies found that considerably more atraditional behavior was elicited with male examiners, suggesting more attention needs to be paid to this variable. Possible mechanisms underlying this effect are discussed.